Opposed piston internal combustion engine



Nov. 2 1937. J. BOGERT ,9

OPPOSED PISTON INTERNAL CQMBQSTION ENGINE Filed Nov. 8, 1954 4Sheets-Sheet 1 N ,1937. J.L.BQGER1 I 1, 91,58

OPPOSED PISTON INTERNAL CQMBUSTION ENGINE Filed Nov. 8, 1934 I4Sheets-Sheef2 46 I 3 44 32 4 N l 32 3/ 2% A 39 38,

C K 7 I 4 9 20 1 4 32 .32 ILL?! I g 3/ Y 3a 25 34 39 v I 32 N I 2. 2 48g 46' 44 I 45 fog/6174a J. L. 'BOGERT v OPPOSED PISTON INTERNALCOMBUSTION ENGINE Nov 2, 1937.

Filed Nov. 8, 1934 4 3032 3/ a2 a/ a2 3/ a2 3/ 32 5/ I a/ w 32 326/ 32.a/ a2 3/ .31 32 a/ 32 a/ a2 Sheets-sheaf; 3

4 Sheets-Shet 4 J. L. BOGERT Fi led Nov. 8, I954 Nov. 2, 1937.

OPPOSED PISTON INTERNAL COMBUSTION ENGINE Patented Nov. 2, 1937 UNITEDSTATES PATENT OFFICE ENGINE John Lawrence Bogart, Brooklyn, N. Y.Application November 8, 1934, Serial No. 752,095

4 Claims.

My invention relates to that form of internal combustion engine wheretwo power-producing pistons reciprocate together simultaneously in thesame cylinder, approaching each other during compression strokes andseparating under the expanding force of the burning compressed fuel andair during power strokes.

The Oechelhauser, Junkers and Doxford enginesbelong to this class andare well known to allskilled in the art. The majority of them areconstructed with but a single crank-shaft, the power producing pistonsbeing link-connected with cranks set degrees apart.

However, engines have been constructed with two crank-shafts, thesecrank-shafts being geared togetherso that they rotate at exactly thesame speed, and the pistons are link connected with cranks out of phaseby 180 degrees. Whether these crank-shafts rotate in the same oropposite directions, so long as their speed of rotation is the same,these pistons will approach and. re-

cede simultaneously in accordance with the fundamental principle of thistype of engine. In

one case the connecting-rods swing together in the same direction acrossthe axis of the cylinder, in the other in opposite directions. In bothcases balance weights attached to the webs of the cranks are necessaryif disturbing forces in the plane of the swing of the connecting-rodsare to be balanced.

Furthermore, with normally long pistons and short connecting-rods, thereis too little room between the crank-shaft and the end of the cyl-linderto permit the withdrawal of the piston whether balance weights beattached to the crank webs or not. This is a most serious defect.

In an opposed piston engine, as normally constructed, which must bereversed, as is the case with marine engines, it is difiicult' tosupercharge the engine since the exhaust ports remain open after thescavenge ports have been covered.

I The objects of my invention are:-

1.-'I'o secure more perfect balance of the disturbing forces set up bythe motion of the reciprocating parts in the plane of theirreciprocation without resorting to the use of crank-shaft balanceweights.

2.To secure a more compact engine taking into consideration the largenumber of powerproducing pistons employed.

3.To produce an engine of large power but low height and low center ofgravity on shipboard and a main propelling unit wholly below the waterline.

- 4.-To render it easy to withdraw any powerproducing piston withoutremoving a crankshaft.

5.To make possible supercharging without resorting to the use ofsupplemental valves in the exhaust passages.

These objects I attain by the peculiar structure I employ and thearrangement of its severalparts, which are fully set forth in theaccompanying drawingswhich constitute part of this specification.Numerals of reference refer to like parts in all the figures.

Fig. 1 is a kinematical drawing which shows the basic reason for myimprovements over the existing state of the art. At the same time italso shows the gearing and mechanism that are fundamental to myinvention.

Fig. 2'is an end elevation of the gear case which encloses the gearingshown in Fig. 1.

Fig. 3 is a vertical transverse section of one of my improved enginesalong the axes of any pair of upper and lower cylinders.

Fig. 4 is a composite drawing of one of my improved engines, part planand part sectional, showing the lower crank-shafts, the main drivinggear and part of the two lower pinionsthat mesh with the main drivinggear, besides the upper exhaust and scavenge air manifolds or conduits.

Fig. 5 is also a composite drawing of one of my improved engines, avertical longitudinal elevation showing the crank-case and gear-casecovers on the left, and vertical transverse sections through the pairsof cylinders at different points on the right show the removablebushings, the scavenging air ports and passages, the fuel injection,relief and air-starting valve locations and the exhaust ports andpassages.

Fig. 6 is a vertical transverse section through the lower half of theengine housing, showing the right and left hand coupling nuts that bindtogether thethrough bolts that join the right and left crank-cases.These through bolts take the entire explosive stresses developed by eachpair of opposed pistons.

Fig. 7 shows a vertical transverse section through a portion of onecylinder and its liner, together with a vertical transverse section of acrank-case bearing, with a tilted piston being withdrawn between thewebs of a crank.

Fig. 8 is an end elevation of a pinion showing oblong driving slots andthe binder bolts which bind the two halves of the pinion together.

Fig. 8a is a longitudinal section through the pinion and its driver,which latter detail is keyed to a shaft which is coupled to acrank-shaft at one or both ends, and transmits the power of these cranksto the pinion.

Fig. 9 is an end elevation of one of my removable bushings, whoseremoval permits the tilting of the piston so that'it can be withdrawnbetween the inner edges of the webs of its crank and the enlarged boreof the cylinder. These bushings are split along a diametral plane.

Fig. 10 is a vertical longitudinal section of one these bushings. l isan upper and 2 a lower cylinder; 3 is an upper left-hand piston, 4 anupper right-hand piston, 5 a lower left-hand piston and 6 a lowerright-handpiston; 1 is an upper left-hand connecting-rod, 8 an upperright-hand connectingrod, 9 a lower left-hand connecting-rod and III alower right-hand connecting-rod; II is an upper left-hand crank, l2 anupper right-hand crank, l3 a lower left-hand crank and I4 a lowerrighthand crank; I5 is an upper left-hand pinion. IS an upper right-handpinion, 11 a lower lefthand pinion and I8 a lower right-hand pinion. I9is the main driving gear with which all the pinions, both upper andlower mesh, and 20 is the main driving shaft which carries main drivinggear I9. It is evident that when the main gear I9 turns anti-clockwiseall the pinions, as indicated by the arrows turn clockwise. As remarkedpreviously, it is not new to gear together two'crankshafts at theopposite ends of a cylinder in which reciprocate two opposed pistons.

The arrows c, which represent in length and direction the centrifugalforce acting at the cranks and the crank-pin ends of the connectin rods,show clearly the vibratory unbalance of the centrifugal forces developedin either the upper or the lower pair of cranks and connecting-rods.when, however, they are combined together in the manner shown in Fig. 1these out of balance forces balance. As indicated by arrows c, the upperpair of cranks and connecting-rods developed a clockwise rocking forcewhich was best balanced by an equal anti-clockwise rocking forcedeveloped by the lower pair of cranks and conmeeting-rods. It should benoted that the upper pair of cranks are in-phase angularly with eachother but out-of-phase with the pair of lower cranks which are alsoin-phase with each other,

the angular displacement being 180 degrees.

Taken together, cylinders I and 2 with their the gear case shown in Fig.2, of which 2lis the lower and 22 the upper half. 23 arethe bearings forthe main gear shaft 20, and 24 are the bearings for the pinion shafts 26which are shown as integral with the pinions in Fig. 8. Thegear casecovers 25 are shown in Figs. 2, 4, and 5. 21 and 28 are the lowercrank-shaft bearings and are shown in Fig. 4.

It 'will be noted that all four crank-shafts are represented as dividedinto two parts by the interposition of the gearing. This is indicated inFigs. 4 and 5, but is not essential. It makes for greater torsionalrigidity of the crank-shaft, and permits the use of smaller diameters.The normal arrangement would be for each eight cranks to be integralwith one crank-shaft, the

gear case and its gearing being at one end instead of in the middle.

29 and 30, shown in Figs. 4 and 5, are the upper 75 and lower flexiblecouplings which relieve he crank-shaft bearing bolts.

pinions of lateral constrain. As in Fig. 4 the gear case is shown partedat horizontal plane C-D, only the four lower flexible couplings 30appear. 3| are the crank housing covers, which can be removed separatelywithout disturbing the bearing bolts 32. These latter are a uniqueconstructional feature of my improved engine. tend across to the middleof the cylinder where they are tapped into nuts 33 shown in Figs. 4 and6. As these bolts have collars on them which fit into counterbores 31shown in Fig. I, it is evident that they by means of their coupling nuts33, constitute ties which bind together the right and left handcrank-shaft housings and the cylinders interposed between into onesolid, rigid structure. At the same time their outer threaded ends,which are beyond their collars serve as These bolts 32 crossing fromcrank-shaft housing 34 to crank-shaft housing 35 through the medium ofnuts 33 are a very important detail, since the explosive force of theburning fuel and air, transmitted by the pistons through theirconnecting-rods to the right-hand and left-hand crank-shafts, calls forthe resiliency that only the length of bolt can They exgive. 36 are thecaps that retain the crank-shaft bearings. The bolts that retain thebearings 24 for the pinion shafts 26 might likewise be carried acrossfrom one side to the other. Pinion covers 25 can be removed withoutdisturbing the practical necessity. Piston rings require replacementfrequently, and one of the great objections to the normal double-actingengine is the necessity of breaking cylinder-head joints;

Taken in conjunction with Fig. 3, Fig. '7 shows very clearly how, byremoving split bushings 38 and constructing the cranks without balance.weights but with their inside faces beveled as at 54, the piston can betilted and withdrawn with its connecting-rod. The cylinder liner 39carries, as usual, the exhaust and. scavenge port openings and at itsmiddle the openings for the fuel valves, the air starting valve and therelief valve. On Fig. 4 two of these valves are shown at 49 and 4|, andin Fig. 5 four of them are shown for each cylinder marked 40, 4|, 42,and 43. The scavenge air trunks or manifolds are shown at 44 in Figs. 3,4, and 5, and 45 is a chamber or conduit connecting each upper row ofscavenge ports with the scavenge ports of its lower companion cylinder.The object of this device is to permit greater freedom of access for thescavenge air to the ports. Inasmuch as the upper and lower cranks aresubstantially 180 degrees apart, the upper scavenge ports are alwaysclosed when the lower are openand vice versa. 46 are exhaust trunks ormanifolds which need no communication between the exhaust ports of i theupper and lower cylinders, since the exhaust cast integrally or built upin sections; the same is true of scavenge-air chamber 45 and distancepiece 41. the crank-shaft housings 34 and 35 are secured to thefoundations, double-bottom or framing of the 48 are the bed-platesthrough which ship. 49 is the coupling through which maindrivcombination is normally known as a quill drive",

and where the pinions are of small diameter in proportion to theirlength is valuable in reducing torsional twist. Here, however, it servesan additional purpose when modified in its construction as I haveindicated in Fig. 8. By making the holes through the driving disc 52 forthe pinion bolts 53 as shown in the drawings, it is possible to give theexhaust port opening lead, both in forward and backing drive. Thepinions on the scavenging side of the engine have reamed holes for'bolts53 while those on the exhaust side have holes which permit an angularmovement of the pinion in relation to disc 52. As soon as starting airis introduced between a pair of pistons, such as 3 and 4 or 5 and 6, thepistons on the exhaust side of the engine move out more rapidly thanthepistons on the scavenge side, and thus establish an exhaust "lead.While these oblong holes are not absolutely essentialto. the successfuloperation of my engine they constitute an important improvement,permitting supercharging, since the exhaust ports, owing to lead willclose earlier. The pinions are made in halves, separating on plane HG.There should be no slackness about the fitting of disc 52 within the rimof the pinions, and preferably friction discs should be interposedbetween the sides of disc 52 and the inner faces of the pinion, so thatthere may be no shock when bolts 53 come in contact with the ends of theslotted holes in the disc.

. removable bushings in the ends Having clearly shown and described thenature of my improvements what I desire to claim as new and useful is:.I

1. In an opposed piston engine having crankshaft housings separated by acylinder, counterbores in said housings,- tie-bolts having collars thatfill said counterbores, coupling nuts that join said tie-bolts together,threads on the outer ends of said tie-bolts beyond their collars, andadjusting nuts on the outer ends of said tie-bolts bearing against a capof a crank-shaft bearing,

substantially as represented and for the purpose set forth.

2. In the cylinder of an opposed piston engine in which twopower-producing pistons reciprocate simultaneously in substantiallyopposite directions, counterboring both ends, of said cylinder, fittingsaid counterbores with bushings divided longitudinally into halves,together with means for securing and releasing said bushings,substantially as represented and forthe purpose set forth.

3. In the cylinder of an opposed piston engine,

a liner in which said pistons reciprocate, said liner having admission,exhaust and fuel-valve openings through its wall, in combination withremovable bushings fitted in counterbores at each end of said cylinder,substantially as represented and for the purpose set forth.

4. In an internal combustion engine, a cylinder, of said cylinder,

a piston which reciprocates within said cylinder,

a crank-shaft and crank webs for said cylinder, means beveling the innerfaces of said crankwebs to facilitate the removal of said piston whentilted.

. JOHN LAWRENCE BOGERT.

